1. Field of the Invention
The present invention relates to a gap filling member for a blanket cylinder for filling the concave portion of a blanket face which is generated along the opening portion of a groove of the blanket cylinder and which is strained and installed by a blanket installing means provided in the groove opening on the outer peripheral face on which a sheet-shaped blanket is wound and with which the initial winding end side and the terminal winding end side are linked through a bar for blanket installation.
2. Description of the Related Art
The fore-mentioned gap filling member for a blanket cylinder (hereinafter, referred to as the “filling member”) is shown in, for example, Japanese Patent Publication (Unexamined) Hei No.8-118603 (hereinafter, referred to as JP-A-8-118603), JP-A-2002-127366 and JP-A-2002-326341.
In JP-A-8-118603, there is described a buffering device for a printing cylinder which can overcome printing hindrances such as shock-streak that is generated by fluctuation of printing pressure, and doubling, by filling a buffering member in a clearance after installing printing equipment parts in the gap provided in printing cylinders such as a printing cylinder and a blanket cylinder, removing the fore-mentioned clearance, and removing the great fluctuation of printing pressure caused by the clearance. Further, the buffering member of the buffering device is formed in one sheet or in multiple sheets in the width direction (longitudinal direction) of the blanket cylinder (printing cylinder). The buffering member consists of a head portion made of an elastic member and a tabular inserting limb having a uniform thickness, the head portion of which is linked with the head portion made of an elastic member by burying the head portion of the limb in the head portion made of an elastic member. The inserting limb can be also filled by being slanted to the radial direction of a printing cylinder, and the outer peripheral face of the head portion is adjusted in a filled condition so as to coincide with the outer peripheral face when a blanket (printing equipment parts) is installed on a blanket cylinder (printing cylinder). When the inserting limb is obliquely inserted against the radial direction of the printing cylinder, it is not sprung from the clearance even if a centrifugal force is formed by rotation of the printing cylinder.
Further, in JP-A-2002-127366, there is described a filling member consisting of a member having rubber elasticity which is filled in a grove along the radius of a blanket cylinder in order to block the groove remaining at the facing portion of the blanket surface along a blanket inserting groove after the blanket is inserted and installed in the blanket inserting groove which is provided on the blanket cylinder. The filling member is formed in a wedge-shaped form, in which a width dimension vertical to a longitudinal direction at an upper face situated at the peripheral face side of the blanket cylinder when it is filled, is larger than the lower face which is a preceding side when it is filled. The filling member further provides a level difference, which carries out an action of preventing drop-out when it is filled, having at least one side of the wedge-shaped form along a longitudinal direction.
Further, in JP-A-2002-326341, there is described a pressuring insertion article having elasticity, which is made of a metal, a rubber or a resin, which is inserted in a non shrinking blanket. The initial winding end vicinity portion and the terminal winding end vicinity portion of the insertion article after winding on a printing cylinder, is inserted in an inserting groove provided in the printing cylinder, by pressuring between the initial end vicinity portion and the terminal end vicinity portion which are inserted in the inserting groove in order to fix it on said printing cylinder. Pressure is exerted on the wall face of the groove by repulsive force compressed by the wall face of the groove through the initial end vicinity portion and the terminal end vicinity portion. Furthermore, as one of the pressuring insertion article, there is described a device of fixing a blanket equipped with a quasi blanket face at its one end, in which the fore-mentioned quasi blanket face is situated on the same peripheral face as the blanket surface wound when it was inserted by pressuring between the fore-mentioned initial end vicinity portion and the terminal end vicinity portion of the blanket wound. The groove of the blanket surface is visually removed and thereby, the invasion of paper powder, an ink and the like are prevented.
However, techniques described in the above-mentioned respective Publications have had problems which should be solved.
Namely, in the buffering member of a buffering device described in JP-A-8-118603, when the tabular inserting limb having a uniform thickness is inserted in the clearance produced after a printing equipment part is installed on a printing cylinder, comparatively great frictional force is created between the inserting limb and the printing equipment part. Accordingly, when the head portion of the buffering member is inserted in the fore-mentioned clearance, the force is created on the linking portion of both in concentration caused by the great difference of compression elastic coefficients between the inserting limb and the printing equipment part. There is a fear that the edge of the tabular inserting limb having rigidity, which can endure the insertion to the clearance, intrudes into the head portion of the elastic member to damage the head portion comprising the elastic member. Therefore a corresponding skilled technique is required for the insertion. Further, when the thickness of the inserting limb is smaller than the fore-mentioned clearance so that the inserting limb can be easily inserted in the clearance of the printing equipment parts, there is no force in the clearance of the printing equipment parts even if the inserting limb is obliquely inserted against the radial direction of the printing cylinder. There has been much fear that the inserting limb is sprung out from the clearance of the printing equipment part by centrifugal force caused by rotation of the printing cylinder during printing operation, is sandwiched between the printing cylinder rotating, and damages these parts.
Further, in the filling member described in JP-A-2002-127366, it is required that the member is filled in the radial direction of the cylinder in the opening portion of the blanket face which was installed in a strained condition approximately parallel to the radial direction of the printing cylinder by the blanket installing means by which the initial end nearby portion of winding the blanket and the terminal end nearby portion of winding were provided in the groove of the cylinder. The filling member remains in the groove without dropping out by a force such as the centrifugal force created by the rotation of the blanket cylinder and created during printing operation. Consequently, the filling member is formed at a sufficiently larger width than the distance of the groove in which it is filled, and when it is filled in the groove, it remains in the groove while strongly pressuring groove walls through the blanket. Therefore, much effort and skill were required to remove this when exchanging the blanket. Further, since the filled edge of the filling member does not reach the bottom of the groove, it is occasionally pushed in the inside of the groove by pressure, which is created in a radius direction. Accordingly, if a groove has a narrowest rim portion at the opening portion in which the inside is formed like an unfolded fan, when the tension of the blanket by the fore-mentioned blanket installing means is released for exchange of the blanket, there is a strong pressure on the wall of the groove through the blanket such that becomes occasionally in a condition in which a force occasionally is created in the inside than the rim portion of the fore-mentioned opening portion. Therefore the removal of the filling member is extremely difficult, the member drops in the groove occasionally, and time is wasted.
Further, in the fixation device of a blanket described in JP-A-2002-326341, fairly great force is required at insertion for firmly fixing the blanket by inserting the pressuring insertion article in the groove so that it is not floated from the outer peripheral face of the printing cylinder and not removed from the groove by vibration and centrifugal force during printing operation. Further, in the fixation device of a blanket in which a quasi blanket face is situated on the same peripheral face as the blanket surface, a skilled technique together with the above-mentioned great force is required in order to insert the pressuring insertion article by pressuring so as to be a uniform depth over the whole length of the groove. Furthermore, in the fixation device of a blanket in which the quasi blanket face is situated on the same peripheral face as the blanket surface and the groove of the blanket surface is visually eliminated, the quasi blanket face is displaced and moved during printing operation in which high printing pressure is created because a space exists under the quasi blanket face. The invasion of paper powder, and ink and the like cannot be prevented perfectly, and the fluctuation of printing pressure is generated by the displacement movement and hindrances, such as shock-streak and doubling which are generated by the fluctuation of printing pressure could not be prevented. Further, when the pressuring insertion article is inserted by pressuring in the fixation device of a blanket, extremely great frictional force is created between the pressuring insertion article and the preceding end and succeeding end of the blanket, and extremely great force is required for the insertion. Not only the above-mentioned great force, but also a skilled technique is required in order to insert the pressuring insertion article by pressuring so as to be a uniform depth over the whole length of the groove so that the quasi blanket face is situated on the same peripheral face as the blanket surface, in like manner as a case of inserting by pressuring the fixation device in which a space exists under the fore-mentioned quasi blanket face.
The present invention solves the above-mentioned problems and provides a filling member in which, although slight force is required for insertion to a blanket cylinder and removal from the blanket cylinder for filling the concave portion of the surface of the blanket cylinder, the insertion to a blanket cylinder and removal from the blanket cylinder can be easily carried out without requiring any skilled technique. Further the filling member is not removed from the blanket cylinder even if centrifugal force is created during printing operation. Further the head portion is not damaged at installation by enabling the installation to the blanket cylinder by comparatively small force, and further the position in which it is installed is not changed by contacting the important points of the wedge-shaped limb portion on one or both of the blanket and a bar for installation of the blanket even if printing pressure and other force is created during printing operation.